using free function after malloc

Have written a function as follows....I am getting an error when I try to free the allocated memory through malloc...
Have put in a commment against the Free functions that are returning an error

Please HELP!

CString getLogFilename()
{
int x,temp;
char *yyyy = (char *)malloc(4);
char *mm = (char *)malloc(2);
char *dd = (char *)malloc(2);
char *zeroCat = (char *)malloc(2);
strcpy(zeroCat,"0");

CTime t = CTime::GetCurrentTime();

CString filename;

char appendDate[8];

/* get the year in yyyy format*/
x = t.GetYear();
_itoa(x,yyyy,10);

/* get the Month in mm format */
x = t.GetMonth();
_itoa(x,mm,10);
if(strlen(mm) == 1){
strcat(zeroCat,mm);
strcpy(mm,zeroCat);
strcpy(zeroCat,"0");
}


/* get the Day in dd format */
x = t.GetDay();
_itoa(x,dd,10);
if(strlen(dd) == 1){
strcat(zeroCat,dd);
strcpy(dd,zeroCat);
}

strcpy(appendDate,yyyy);
strcat(appendDate,mm);
strcat(appendDate,dd);

filename = appendDate;

free(yyyy); /*Error */
free(mm); /*Error */
free(dd); /*Error */
free(zeroCat); /*Error */
free(appendDate); /*Error */

return filename;
}

First of all, you have to allocate n + 1 chars for a string of length n, because of the trailing 0 meaning end of string.

You have not allocated the memory for appendDate with malloc - that is the cause of the crush. You should have used static arrays instead of dynamic memory allocation as it is inappropriate here.

Quote:

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Originally posted by Yves M
First of all, you have to allocate n + 1 chars for a string of length n, because of the trailing 0 meaning end of string.

---

Thanks Yves....it is working now.

Also is there a way of shortening the whole program using wsprintf ?

Quote:

---

Originally posted by Alexey B
You have not allocated the memory for appendDate with malloc - that is the cause of the crush. You should have used static arrays instead of dynamic memory allocation as it is inappropriate here.

---

yes Alexei...I have now fixed this problem..and it is working now thanks heaps

Quote:

---

Also is there a way of shortening the whole program using wsprintf?

---

sscanf or CString::Format can shorten your code a great deal:

Code:

---

CString getLogFilename()
{
        CTime time = CTime::GetCurrentTime();
        CString filename;
        output.Format("%i/%i/%i", time.GetYear(), time.GetMonth(), time.GetDay());
       
        return filename;
}

---

you can try this way...

CString getLogFileName()
{
CString strFileName;
SYSTEMTIME st;

::GetLocalTime(st);

strFileName.Format(TEXT("%04d%02d%02d", st.wYear, st.wMonth, st.wDay);

return strFileName;
}

bye,
m_l

[QUOTE]quote:
--------------------------------------------------------------------------------
Also is there a way of shortening the whole program using wsprintf?
--------------------------------------------------------------------------------

sscanf or CString::Format can shorten your code a great deal:
code:--------------------------------------------------------------------------------CString getLogFilename()
{
CTime time = CTime::GetCurrentTime();
CString filename;
output.Format("%i/%i/%i", time.GetYear(), time.GetMonth(), time.GetDay());

return filename;
}
QUOTE]

Even simpler to use CTime::Format.

Code:

---


CString getLogFilename()
{
        CTime time = CTime::GetCurrentTime();
        CString filename = time.Format("%Y/%m/%d");       
        return filename;
}

---

Code:

---

inline CString getLogFilename()
{
        return CTime::GetCurrentTime().Format("%Y/%m/%d");
}

---

:eek: